1. Field of the Invention
The present invention pertains to thermal battery cells. More particularly, it pertains to such cells wherein activation is brought about at a much lower temperature and the electrolyte is also used as the oxidizer.
2. DESCRIPTION OF THE PRIOR ART
Thermal battery cells contain an electrolyte that is solid and non-conductive at normal temperatures but becomes ionically conductive when a built-in pyrotechnic heat source activates the battery by melting the solid electrolyte. Such characteristics make thermal batteries capable of essentially unlimited storage life and of rapid and reliable activation. Thus, such batteries can be designed to withstand severe shock and vibrations and are ideally suited for use in military, aerospace, and emergency applications.
Generally, such thermal batteries utilized in missile systems are activated at temperatures above 352.degree. C. and make use of a LiCl--KCl mixture as the electrolyte, calcium metal as the anode, and CaCrO.sub.4 as the cathodic material. In such a system, a complex series of chemical and electrochemical reactions occur at the anode to form a liquid calcium-lithium alloy, a KCl-CaCl.sub.2 double salt (M.P. 752.degree. C.) and a Ca.sub.2 CrO.sub.4 Cl layer adjacent to the anode. Due to these complex interactions, thermal batteries using LiCl--KCl mixtures are generally designed to operate at internal temperatures between 475.degree. C. and 550.degree. C.